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VirtualChannelInit (Windows Embedded CE 6.0)

  • Article

1/6/2010

This function registers the names of the virtual channels that it wants to access. It reserves the names for use by an application, but does not open the channels. This function must be called before the client connects to the server. Therefore, the DLL's initialization procedure should call this function.

Syntax

typedef UINT VCAPITYPE VIRTUALCHANNELINIT(
  LPVOID FAR * ppInitHandle,
  PCHANNEL_DEF pChannel,
  INT channelCount,
  ULONG versionRequested,
  PCHANNEL_INIT_EVENT_FN pChannelInitEventProc
);

Parameters

  • ppInitHandle
    [in] Pointer to a variable that receives a handle identifying the client connection. Use this handle to identify the client in subsequent calls to the VirtualChannelOpen function.
  • pChannel
    [in, out] Pointer to an array of CHANNEL_DEF structures. Each structure contains the name and initialization options of a virtual channel that the client DLL opens. The VirtualChannelInit function call does not open these virtual channels; it only reserves the names for use by this application.
  • channelCount
    [in] Specifies the number of channels that are registered. This is the number of CHANNEL_DEF structures in the pChannel parameter.
  • versionRequested
    [in] Specifies the level of virtual channel support that is requested. Set this parameter to VIRTUAL_CHANNEL_VERSION_WIN2000.

Return Value

The following table shows the return values for this function.

Value Description

CHANNEL_RC_OK

Function succeeded.

CHANNEL_RC_ALREADY_CONNECTED

The client is already connected to a Terminal Server.

CHANNEL_RC_NOT_IN_VIRTUALCHANNELENTRY

VirtualChannelInit was not called from within your VirtualChannelEntry function.

CHANNEL_RC_TOO_MANY_CHANNELS

The pChannel parameter has more channels than can be registered. Therefore, none of the channels were registered. The maximum number of channels allowed per client is CHANNEL_MAX_COUNT.

CHANNEL_RC_BAD_CHANNEL

The pChannel parameter is incorrect or the syntax for one of the channel names is incorrect.

CHANNEL_RC_BAD_INIT_HANDLE

The ppInitHandle parameter is incorrect.

CHANNEL_RC_BAD_PROC

The pChannelInitEventProc parameter is incorrect.

Remarks

Terminal Services provides a pointer to a VirtualChannelInit function in the CHANNEL_ENTRY_POINTS structure passed to your VirtualChannelEntry entry point.

You can call VirtualChannelInit only from your VirtualChannelEntry function. Calls to VirtualChannelInit at any other time will fail.

When VirtualChannelInit returns successfully, Terminal Services has registered the requested channels. However, Terminal Services might not have completed other initializations. When the initialization process has completed, Terminal Services calls your VirtualChannelInitEvent callback function, passing in the CHANNEL_EVENT_INITIALIZED event.

Do not make assumptions about the number of available virtual channels before calling this function, because the system and other plug-ins may have reserved virtual channels. You should always check for the CHANNEL_RC_TOO_MANY_CHANNELS return code after calling this function.

When VirtualChannelInit returns, the options member of each CHANNEL_DEF structure includes CHANNEL_OPTION_INITIALIZED if the channel was successfully initialized.

The maximum number of channels per client session is CHANNEL_MAX_COUNT.

A client plug-in can declare a channel as remote control persistent. This is done by specifying CHANNEL_OPTION_REMOTE_CONTROL_PERSISTENT in a CHANNEL_DEF structure pointed to by the pChannel parameter. For more information, see Remote-Control Persistent Virtual Channels.

Requirements

Header cchannel.h
Library Developer Implemented
Windows Embedded CE Windows CE .NET 4.0 and later

See Also

Reference

RDP Functions